When using a hierarchical network such as the Internet for communications, interruptions in communications due to network unavailability are common. Typically, a local area network (LAN) at a lower level of the hierarchy is connected to a wide area network (WAN) at a higher level of the hierarchy through a gateway or other network device that accesses both networks. Network congestion or possibly a temporary loss of connection on the WAN may require network devices on the LAN to momentarily suspend their access in terms of deferring the sending or receiving of data. In an application of transferring text or data files, the delays that are incurred due to deferral are not usually significant since text and data files do not need to be delivered in real-time, meaning there is generally no time boundary for completion of the transfer. Therefore, the typically short delays incurred do not generally inhibit the successful communication of information.
Even in the case where a LAN connection to the Internet is made wirelessly, if the application is text or data transfer, an interruption causes the transfer to pause until the network is available in order to continue sending or receiving the necessary information. However, when the application requires a lower latency in message transfer as typified by streaming audio and/or video, teleconferencing, and voice over Internet Protocol (VoIP), delays due to network unavailability are not desirable. For example, although a traditional wireless network device can usually give some indication of the status of the direct wireless connection, a traditional wireless network device is not aware of the availability status of an indirectly connected network, such as the WAN, which may affect the latency of communications with the wireless device and cause disruption in some applications. Accordingly, there is a need in the art for a network device to determine the availability status of a network other than the network to which the network device is directly connected. Additionally, there is a need in the art for a network device to determine the availability status of a network before directly connecting to the network device.
Embodiments of the present invention and their advantages are best understood by referring to the detailed description that follows. It should be appreciated that like reference numerals are used to identify like elements illustrated in the figures.